Sealing members, articles using the same and methods of reducing sticktion

ABSTRACT

The present invention provides rubber sealing members having an exterior surface adapted to sealingly engage an inner surface of a chamber of the medical device, the exterior surface of the sealing member having a coating thereon prepared from a curable composition including: (a) a first organopolysiloxane having at least two alkenyl groups; and (b) a second organopolysiloxane having at least two pendant hydrogen groups, the second organopolysiloxane being different from the first organopolysiloxane, wherein at least one of the first organopolysiloxane, the second organopolysiloxane or an optional third organopolysiloxane of the curable composition comprises a fluoro group.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/693,293, filed on Mar. 29, 2007, now U.S. Pat. No. 7,943,242, whichclaims the benefit of priority from U.S. Patent Application No.60/787,327, filed on Mar. 30, 2006, each of which are incorporated byreference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a rubber sealing member for a medical device,such as a syringe assembly, coated with a composition comprising curableorganopolysiloxane(s), methods to reduce static and kinetic frictionbetween slidable surfaces; and articles of low friction preparedthereby.

2. Description of Related Art

Certain devices require slow and controlled initiation and maintenanceof sliding movement of one surface over another surface. It is wellknown that two stationary surfaces having a sliding relationship oftenexhibit sufficient resistance to initiation of movement that graduallyincreased pressure applied to one of the surfaces does not causemovement until a threshold pressure is reached, at which point a suddensliding separation of the surfaces takes place. This sudden separationof stationary surfaces into a sliding relationship is herein referred toas “breakout”.

A less well known, but important frictional force is “breakloose force”,which refers to the force required to overcome static friction betweensurfaces of a syringe assembly that has been subjected to autoclavingand may have a slight deformation in one or both of the contactingsurfaces of the syringe assembly, for example in the syringe barrel. Inaddition to autoclaving, parking of the assembly can further increasethe breakloose force.

Breakout and breakloose forces are particularly troublesome in liquiddispensing devices, such as syringes, used to deliver small, accuratelymeasured quantities of a liquid by smooth incremental line to lineadvancement of one surface over a graduated second surface. The problemis also encountered in devices using stopcocks, such as burets, pipets,addition funnels and the like where careful dropwise control of flow isdesired.

The problems of excessive breakout and breakloose forces are related tofriction. Friction is generally defined as the resisting force thatarises when a surface of one substance slides, or tends to slide, overan adjoining surface of itself or another substance. Between surfaces ofsolids in contact, there may be two kinds of friction: (1) theresistance opposing the force required to start to move one surface overanother, conventionally known as static friction, and (2) the resistanceopposing the force required to move one surface over another at avariable, fixed, or predetermined speed, conventionally known as kineticfriction.

The force required to overcome static friction and induce breakout isreferred to as the “breakout force”, and the force required to maintainsteady slide of one surface over another after breakout or breakloose isreferred to as the “sustaining force”. Two main factors contribute tostatic friction and thus to the breakout or breakloose force. The term“stick” as used herein denotes the tendency of two surfaces instationary contact to develop a degree of adherence to each other. Theterm “inertia” is conventionally defined as the indisposition to motionwhich must be overcome to set a mass in motion. In the context of thepresent invention, inertia is understood to denote that component of thebreakout force which does not involve adherence.

Breakout or breakloose forces, in particular the degree of stick, varyaccording to the composition of the surfaces. In general, materialshaving elasticity show greater stick than non-elastic materials,particularly when the surfaces are of dissimilar composition. The lengthof time that surfaces have been in stationary contact with each otheralso influences breakout and/or breakloose forces. In the syringe art,the term “parking” denotes storage time, shelf time, or the intervalbetween filling and discharge. Parking generally increases breakout orbreakloose force, particularly if the syringe has been refrigeratedduring parking.

A conventional approach to overcoming breakout has been application of alubricant to a surface to surface interface. Common lubricants used arehydrocarbon oils, such as mineral oils, peanut oil, vegetable oils andthe like. Such products have the disadvantage of being soluble in avariety of fluids, such as vehicles commonly used to dispensemedicaments. In addition, these lubricants are subject to air oxidationresulting in viscosity changes and objectionable color development.Further, they are particularly likely to migrate from the surface tosurface interface. Such lubricant migration is generally thought to beresponsible for the increase in breakout force with time in parking.

Silicone oils are also commonly used as lubricants. They are poorsolvents and are not subject to oxidation, but migration and stick dooccur, and high breakout forces are a problem. Polytetrafluoroethylenesurfaces provide some reduction in breakout forces, but this material isvery expensive, and the approach has not been totally effective.

Thus there is a need for a better system to overcome high breakout andbreakloose forces whereby smooth transition of two surfaces fromstationary contact into sliding contact can be achieved.

SUMMARY OF THE INVENTION

In some embodiments, the present invention provides a rubber sealingmember for a medical device, the sealing member having an exteriorsurface adapted to sealingly engage an inner surface of a chamber of themedical device, the exterior surface of the sealing member having acoating thereon prepared from a curable composition comprising:

(a) a first organopolysiloxane comprising at least two alkenyl groups;and

(b) a second organopolysiloxane comprising at least two pendant hydrogengroups, the second organopolysiloxane being different from the firstorganopolysiloxane, wherein at least one of the firstorganopolysiloxane, the second organopolysiloxane or an optional thirdcomponent of the curable composition comprises at least one fluorogroup.

In some embodiments, the present invention provides articles ofmanufacture, such as medical devices, comprising the rubber sealingmember of the present invention.

In some embodiments, the present invention provides a method forlubricating the interface between an inner surface of a chamber and anexterior surface of a rubber sealing member of a medical device,comprising the steps of:

(a) applying a coating onto the exterior surface of the rubber sealingmember, the coating being prepared from a curable compositioncomprising:

-   -   (i) a first organopolysiloxane comprising at least two alkenyl        groups; and    -   (ii) a second organopolysiloxane comprising at least two pendant        hydrogen groups, the second organopolysiloxane being different        from the first organopolysiloxane,

wherein at least one of the first organopolysiloxane, the secondorganopolysiloxane or an optional third component of the curablecomposition comprises at least one fluoro group; and

(b) at least partially crosslinking the coating of step (a).

In other embodiments, the present invention provides a method forreducing breakout force or breakloose force between an inner surface ofa chamber and an exterior surface of a rubber sealing member of amedical device, comprising the steps of:

(a) applying a coating onto the exterior surface of the rubber sealingmember, the coating being prepared from a curable compositioncomprising:

-   -   (i) a first organopolysiloxane comprising at least two alkenyl        groups; and    -   (ii) a second organopolysiloxane comprising at least two pendant        hydrogen groups, the second organopolysiloxane being different        from the first organopolysiloxane,

wherein at least one of the first organopolysiloxane, the secondorganopolysiloxane or an optional third component of the curablecomposition comprises at least one fluoro group; and

(b) at least partially crosslinking the coating of step (a).

In other embodiments, the present invention provides a method forreducing sustaining force between an inner surface of a chamber and anexterior surface of a rubber sealing member of a medical device,comprising the steps of:

(a) applying a coating onto the exterior surface of the rubber sealingmember, the coating being prepared from a curable compositioncomprising:

-   -   (i) a first organopolysiloxane comprising at least two alkenyl        groups; and    -   (ii) a second organopolysiloxane comprising at least two pendant        hydrogen groups, the second organopolysiloxane being different        from the first organopolysiloxane,

wherein at least one of the first organopolysiloxane, the secondorganopolysiloxane or an optional third component of the curablecomposition comprises at least one fluoro group; and

(b) at least partially crosslinking the coating of step (a).

In other embodiments, the present invention provides a method forreducing breakloose and sustaining forces between an inner surface of achamber and an exterior surface of a rubber sealing member of a medicaldevice, comprising the steps of:

(a) applying a coating onto the exterior surface of the rubber sealingmember, the coating being prepared from a curable compositioncomprising:

-   -   (i) a first organopolysiloxane comprising at least two alkenyl        groups; and    -   (ii) a second organopolysiloxane comprising at least two pendant        hydrogen groups, the second organopolysiloxane being different        from the first organopolysiloxane,

wherein at least one of the first organopolysiloxane, the secondorganopolysiloxane or an optional third component of the curablecomposition comprises at least one fluoro group; and

(b) at least partially crosslinking the coating of step (a).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will best be understood from the followingdescription of specific embodiments when read in connection with theaccompanying drawings:

FIG. 1 is a graph of infusion pump actuation force test results at afeed rate of 0.1 ml/hr for a prior art syringe assembly;

FIG. 2 is a graph of infusion pump actuation force test results at afeed rate of 1.0 ml/hr for a prior art syringe assembly;

FIG. 3 is a graph of infusion pump actuation force test results at afeed rate of 10 ml/hr for a prior art syringe assembly;

FIG. 4 is a graph of infusion pump actuation force test results at afeed rate of 0.1 ml/hr for a syringe assembly according to the presentinvention;

FIG. 5 is a graph of infusion pump actuation force test results at afeed rate of 1.0 ml/hr for a syringe assembly according to the presentinvention;

FIG. 6 is a graph of infusion pump actuation force test results at afeed rate of 10 ml/hr for a syringe assembly according to the presentinvention; and

FIG. 7 is a graph of infusion pump actuation force test results at afeed rate of 10 ml/hr for a syringe assembly according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, andso forth used in the specification and claims are to be understood asbeing modified in all instances by the term “about.” Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Furthermore, when numerical ranges ofvarying scope are set forth herein, it is contemplated that anycombination of these values inclusive of the recited values may be used.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between andincluding the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

The present invention provides a rubber sealing member having anexterior surface adapted to sealingly engage an inner surface of achamber of a medical device. The respective surfaces can be infrictional engagement. When used in a medical device, the rubber sealingmember of the present invention can reduce the force required to achievebreakout, breakloose and/or sustaining forces, whereby transition ofsurfaces from stationary contact to sliding contact occurs without asudden surge. When breakout or breakloose is complete and the surfacesare in sliding contact, they slide smoothly upon application of very lowsustaining force. Substantially less lubricant may be required andlubricant migration is reduced or eliminated. The effect achieved by thesealing member and methods of the present invention can be of longduration, and articles, such as syringes, can retain the advantages oflow breakout, low breakloose and sustaining forces throughout anyparking period. When the sealing member is part of a liquid dispensingdevice, small highly accurate increments of liquid may be dispensedrepeatedly without sudden surges. Thus, a syringe including a rubbersealing member treated according to the present invention can be used toadminister a medicament to a patient without the danger of surgeswhereby accurate control of dosage and greatly enhanced patient safetyare realized.

Non-limiting examples of medical devices include syringe assemblies,syringe pumps, drug cartridges, needleless injectors, liquid dispensingdevices and liquid metering devices. In some embodiments, the medicaldevice is a syringe assembly comprising a first component which is asealing member and a second component which is a syringe barrel.

The rubber sealing member can be formed from any elastomeric material.Elastomers are used in many important and critical applications inmedical devices and pharmaceutical packaging. As a class of materials,their unique characteristics, such as flexibility, resilience,extendability, and sealability, have proven particularly well suited forproducts such as catheters, syringe tips, drug vial articles, injectionsites, tubing, gloves and hoses. Three primary synthetic thermosetelastomers typically are used in medical applications: polyisoprenerubber, silicone rubber, and butyl rubber. Of the three rubbers, butylrubber has been the most common choice for articles due to its highcleanness and permeation resistance which enables the rubber to protectoxygen- and water-sensitive drugs.

Suitable butyl rubbers useful in the method of the present inventioninclude copolymers of isobutylene (about 97-98%) and isoprene (about2-3%). The butyl rubber can be halogenated with chlorine or bromine.Suitable butyl rubber vulcanizates can provide good abrasion resistance,excellent impermeability to gases, a high dielectric constant, excellentresistance to aging and sunlight, and superior shock-absorbing andvibration-damping qualities to articles formed therefrom.

Other useful elastomeric copolymers include, without limitation, styrenecopolymers such as styrene-butadiene (SBR or SBS) copolymers,styrene-isoprene (SIS) block polymers or styrene-isoprene/butadiene(SIBS), in which the content of styrene in the styrene block copolymerranges from about 10% to about 70%, and preferably from about 20% toabout 50%. The rubber composition can include, without limitation,antioxidants and/or inorganic reinforcing agents to preserve thestability of the rubber composition.

In some embodiments, the sealing member can be a stopper, O-ring,plunger tip or piston, for example. Syringe plunger tips or pistonstypically are made of a compressible, resilient material such as butylrubber, because of the vulcanized rubber's ability to provide a sealbetween the plunger and interior housing of the syringe. Syringeplungers, like other equipment used in the care and treatment ofpatients, have to meet high performance standards, such as the abilityto provide a tight seal between the plunger and the barrel of thesyringe.

The coating is applied to at least a portion of at least one surface ofthe rubber sealing member to be placed in frictional engagement with anopposed surface of another component. The other component of the medicaldevice, such as the barrel, can be coated with a coating as describedbelow for the sealing member, a polydimethylsiloxane coating oruncoated, as desired. Methods for coating the surface(s) are discussedin detail below.

The rubber sealing member of the present invention is coated with acured coating prepared from a composition comprising a firstorganopolysiloxane comprising at least two alkenyl groups; and (b) asecond organopolysiloxane comprising at least two pendant hydrogengroups, the second organopolysiloxane being different from the firstorganopolysiloxane, wherein at least one of the firstorganopolysiloxane, the second organopolysiloxane or an optional thirdcomponent of the curable composition comprises at least one fluorogroup, as described in detail below. As used herein, the term “cure” asused in connection with a composition, e.g., a “cured composition” or a“cured coating” shall mean that at least a portion of the crosslinkablecomponents which form the composition are at least partiallycrosslinked. As used herein, the term “curable”, as used in connectionwith a component of the composition, means that the component hasfunctional groups capable of being crosslinked, for example alkenylgroups such as vinyl groups. In certain embodiments of the presentinvention, the crosslink density of the crosslinkable components, i.e.,the degree of crosslinking, ranges from 5% to 100% of completecrosslinking. One skilled in the art will understand that the presenceand degree of crosslinking, i.e., the crosslink density, can bedetermined by a variety of methods, such as dynamic mechanical thermalanalysis (DMTA) using a TA Instruments DMA 2980 DMTA analyzer conductedunder nitrogen. This method determines the glass transition temperatureand crosslink density of free films of coatings or polymers. Thesephysical properties of a cured material are related to the structure ofthe crosslinked network.

As discussed above, the coating composition comprises one or more first,curable organopolysiloxane(s) comprising at least two alkenyl groups.Each alkenyl group of the first organopolysiloxane (a) can beindependently selected from the group consisting of vinyl, allyl,propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl anddecenyl. One skilled in the art would understand that the firstorganopolysiloxane (a) can comprise one or more of any of the abovetypes of alkenyl groups and mixtures thereof. In some embodiments, atleast one alkenyl group is vinyl. Higher alkenyl or vinyl contentprovides more efficient crosslinking.

In some embodiments, the first organopolysiloxane (a) can be representedby the following structural formulae (I) or (II):

wherein R is alkyl, haloalkyl, aryl, haloaryl, cycloalkyl,silacyclopentyl, aralkyl and mixtures thereof; X is about 60 to about1000, preferably about 200 to about 320; and y is about 3 to about 25.Copolymers and mixtures of these polymers are also contemplated.

Non-limiting examples of useful first organopolysiloxanes (a) include:vinyldimethyl terminated polydimethylsiloxanes; vinylmethyl,dimethylpolysiloxane copolymers; vinyldimethyl terminated vinylmethyl,dimethylpolysiloxane copolymers; divinylmethyl terminatedpolydimethylsiloxanes; polydimethylsiloxane, mono vinyl, monon-butyldimethyl terminated; and vinylphenylmethyl terminatedpolydimethylsiloxanes.

In some embodiments, a mixture of siloxane polymers selected from thoseof Formulae I and/or II can be used. For example, the mixture cancomprise two different molecular weight vinyldimethylsilyl terminatedpolydimethylsiloxane polymers, wherein one of the polymers has anaverage molecular weight of about 5,000 to about 25,000 and preferablyabout 16,000, and the other polymer has an average molecular weight ofabout 30,000 to about 75,000 and preferably about 38,000. Generally, thelower molecular weight siloxane can be present in amounts of about 20%to about 80%, such as about 60% by weight of this mixture; and thehigher molecular weight siloxane can be present in amounts of about 80%to about 20%, such as about 40% by weight of this mixture.

Another non-limiting example of a suitable first organopolysiloxane (a)is (7.0-8.0% vinylmethylsiloxane)-dimethylsiloxane copolymer,trimethylsiloxy terminated, such as VDT-731 vinylmethylsiloxanecopolymer which is commercially available from Gelest, Inc. ofMorrisville, Pa.

In some embodiments, the first organopolysiloxane (a) can furthercomprise one or more fluoro groups, such as —F or fluoroalkyl groupssuch as trifluoromethyl groups.

In some embodiments, the first organopolysiloxane (a) can furthercomprise one or more alkyl and/or one or more aryl groups, such asmethyl groups, ethyl groups or phenyl groups, respectively.

Generally, the viscosity of the alkenyl-substituted siloxanes can rangefrom about 200 to about 1,000,000 cst.

In some embodiments, the first organopolysiloxane (a) comprises about 5to about 50 weight percent of the composition. In other embodiments, thefirst organopolysiloxane (a) comprises about 10 to about 40 weightpercent of the composition. In other embodiments, the firstorganopolysiloxane (a) comprises about 15 to about 30 weight percent ofthe composition.

While not wishing to be bound by any theory, it is believed that thealkenyl functional siloxanes can increase the viscosity of the coatingand improve binding between the coating and the coated surface.

The composition also comprises one or more second organopolysiloxane(s)(b) comprising at least two pendant hydrogen groups, the secondorganopolysiloxane (b) being different from the firstorganopolysiloxane, for example having different types of atom(s) ordifferent numbers of atoms in the respective organopolysiloxanes.

Non-limiting examples of suitable organopolysiloxanes (b) comprising atleast two pendant hydrogen groups include organopolysiloxanes havingpendant hydrogen groups along the polymer backbone or terminal hydrogengroups. In some embodiments, the organopolysiloxane can be representedby the following structural formulae (V):

wherein p is about 8 to about 12, for example about 10. In otherembodiments, the organopolysiloxane can be represented by the followingstructural formula (VI):HMe₂SiO(Me₂SiO)_(p)SiMe₂H  (VI)wherein p is about 140 to about 170, for example about 150 to about 160.A mixture of these polymers can be used comprising two differentmolecular weight materials. For example, about 2% to about 5% by weightof the mixture of a trimethyl silyl terminatedpolymethylhydrogensiloxane having an average molecular weight of about400 to about 7,500, for example about 1900, can be used in admixturewith about 98% to about 95% of a dimethylhydrogen silyl-terminatedpolymethylhydrogensiloxane having an average molecular weight of about400 to about 37,000 and preferably about 12,000. In some embodiments,the mole ratio of vinyl groups to hydrogen groups in the reactivecomponent is about 0.010:1 to about 0.20:1. In some embodiments, themole ratio of hydrogen groups of the crosslinking polymer to hydrogengroups of the chain-extending polymer is about 5.0:1 to about 20:1.Non-limiting example of useful organopolysiloxanes comprising at leasttwo pendant hydrogen groups include dimethylhydro terminatedpolydimethylsiloxanes; methylhydro, dimethylpolysiloxanecopolymers;methylhydro terminated methyloctyl siloxane copolymers; and methylhydro,phenylmethyl siloxane copolymers.

In some embodiments, the second organopolysiloxane (b) can furthercomprise one or more fluoro groups, such as —F or fluoroalkyl groupssuch as trifluoromethyl groups.

In some embodiments, the second organopolysiloxane (b) can furthercomprise one or more alkyl and/or one or more aryl groups, such asmethyl groups, ethyl groups or phenyl groups, respectively.

Generally, the viscosity of the hydrogen substituted siloxane can rangefrom about 100 to about 1,000,000 cst.

In some embodiments, the second organopolysiloxane (b) comprises about 1to about 40 weight percent of the composition. In other embodiments, thesecond organopolysiloxane (b) comprises about 5 to about 30 weightpercent of the composition. In other embodiments, the secondorganopolysiloxane (b) comprises about 10 to about 30 weight percent ofthe composition.

In some embodiments, the composition can further comprise one or morethird components comprising at least one fluoro group, for examplefluorine groups and/or fluoroalkyl groups. Non-limiting examples of suchthird components comprise one or more fluorocarbon oligomers,fluorocarbon polymers and/or fluoro organopolysiloxanes, such aspolytetrafluoroethylene, polymers of chlorotrifluoroethylene,fluorinated ethylene-propylene polymers, polyvinylidene fluoride,hexafluoropropylene, and the like, preferably suitable for medicalapplications.

When present, the third component can comprise about 0.1 to about 20weight percent of the composition. In other embodiments, the thirdcomponent comprises about 0.1 to about 10 weight percent of thecomposition.

In some embodiments, the composition can further comprise one or morecyclic siloxane(s), for example octamethylcyclotetrasiloxane and/ordecamethylcyclopentasiloxane. In some embodiments, the cyclic siloxanecomprises about 5 to about 80 weight percent of the composition. Inother embodiments, the cyclic siloxane comprises about 20 to about 80weight percent of the composition. In other embodiments, the cyclicsiloxane comprises about 40 to about 80 weight percent of thecomposition.

In some embodiments, the composition further comprises one or moreorganopolysiloxane(s) different from the first and secondorganopolysiloxanes, for example siloxanes of Formula (IV) shown below,such as alkyl siloxanes.

Non-limiting examples of such organopolysiloxanes can be represented bythe following structural formula (IV):

wherein R is alkyl, haloalkyl, aryl, haloaryl, cycloalkyl,silacyclopentyl, aralkyl and mixtures thereof; and Z is about 20 toabout 1,800. In some embodiments, the organopolysiloxanes of Formula(IV) can be represented by the following structural formula (IVA):

wherein Z can be as above, or for example can be about 70 to about 1800or about 70 to about 1,350. The average molecular weight of theorganopolysiloxane of Formula (IV) can be about 1900 to about 100,000,and preferably about 5,000 to about 100,000. Generally, this correspondswith a viscosity of about 20 to about 300,000 centistokes (cst).

A non-limiting example of a suitable alkyl organosiloxane ispolydimethylsiloxane. The viscosity of the alkyl organosiloxane canrange from about 100 to about 1,000,000 cst, and in some embodiments canrange from about 12,500 to about 100,000 cst. In some embodiments, thealkyl organosiloxane comprises about 1 to about 20 weight percent of thecomposition. In other embodiments, the alkyl organosiloxane comprisesabout 1 to about 10 weight percent of the composition. In otherembodiments, the alkyl organosiloxane comprises about 1 to about 5weight percent of the composition.

In some embodiments, the composition further comprises silica, which canadjust the hardness of the coating. In some embodiments, the silicacomprises about 1 to about 15 weight percent of the composition. Inother embodiments, the silica comprises about 1 to about 10 weightpercent of the composition. In other embodiments, the silica comprisesabout 1 to about 5 weight percent of the composition.

In some embodiments, the composition further comprises a catalyticamount of a catalyst for promoting crosslinking of the firstorganopolysilaxane (a) and the second organopolysiloxane (b).Non-limiting examples of suitable catalysts for promoting heat cureinclude platinum or rhodium group metal catalysts, such as Karstedtcatalyst Pt₂{[(CH₂═CH)Me₂Si]₂O}₃ or peroxide catalysts, such as dicumylperoxide The catalyst can be present in an amount ranging from about0.001 to about 0.05 weight percent of the composition.

The components of the composition can be formulated in a singlecomposition or two compositions that are mixed prior to application, forexample to separate a catalyst from crosslinkable components untilshortly before application. A non-limiting example of a suitablecomposition is a two-part composition commercially available from GEAdvanced Materials as LSR Topcoat Parts A and B, which are mixed beforeapplication to the rubber sealing member. According to a Material SafetyData Sheet dated Jan. 20, 2004, LSR Topcoat Part A contains greater thanabout 99% decamethylcyclopentasiloxane and less that about 1%octamethylcyclotetrasiloxane. According to a Material Safety Data Sheetdated Jan. 22, 2004, LSR Topcoat Part B contains greater than about 50%decamethylcyclopentasiloxane, less than about 25% vinyl-terminatedpolydimethylsiloxane, less than 10% synthetic amorphous silica,precipitated, less than 5% polydimethylsiloxane, and greater than 10% ofsilanic hydrogen fluid. Part A and Part B can be mixed up to about a daybefore application to the rubber sealing member, and are preferablymixed shortly before application. Generally, about 50 weight percent ofPart A and about 50 weight percent of Part B are used to prepare thecomposition, although the relative amounts can be varied if desired.

In some embodiments, the composition can further comprise one or morecurable organopolysiloxane(s) comprising at least two polar groups,being different from the first organopolysiloxane(s) and secondorganopolysiloxane(s), for example having different types of atom(s) ordifferent numbers of atoms in the respective organopolysiloxanes.

Each polar group of the organopolysiloxane can be independently selectedfrom the group consisting of acrylate, methacrylate, amino, imino,hydroxy, epoxy, ester, alkyloxy, isocyanate, phenolic, polyurethaneoligomeric, polyamide oligomeric, polyester oligomeric, polyetheroligomeric, polyol, carboxypropyl, and fluoro groups. One skilled in theart would understand that the organopolysiloxane can comprise one ormore of any of the above polar groups and mixtures thereof. Preferably,these organopolysiloxanes are not moisture-curable.

In some embodiments, the polar groups are acrylate groups, for exampleacryloxypropyl groups. In other embodiments, the polar groups aremethacrylate groups, such as methacryloxypropyl groups.

The organopolysiloxane having polar groups can further comprise one ormore alkyl groups and/or aryl groups, such as methyl groups, ethylgroups or phenyl groups.

A non-limiting example of such an organopolysiloxane is [15-20%(acryloxypropyl)methylsiloxane]-dimethylsiloxane copolymer, such asUMS-182 acrylate functional siloxane which is commercially availablefrom Gelest, Inc. of Morrisville, Pa. Other useful organopolysiloxanes(b) include polyfluoroalkylmethyl siloxanes and fluoroalkyl, dimethylsiloxane copolymers.

In other embodiments, such an organopolysiloxane can be represented bythe formula (III):

wherein R₁ is selected from the group consisting of acrylate,methacrylate, amino, imino, hydroxy, epoxy, ester, alkyloxy, isocyanate,phenolic, polyurethane oligomeric, polyamide oligomeric, polyesteroligomeric, polyether oligomeric, polyol, carboxypropyl, and fluorogroups; and R₂ is alkyl, n ranges from 2 to 4, and x is an integersufficient to give the lubricant a viscosity of about 10 to 2,000,000cst.

In some embodiments, the organopolysiloxane having polar groupscomprises about 1 to about 40 weight percent of the composition, inother embodiments about 3 to about 20 weight percent, and in otherembodiments, about 1 to about 20 weight percent of the composition.

While not wishing to be bound by any theory, it is believed that thepolar siloxanes may be present on top of the coated surface to helpreduce the coefficient of friction between the engaged surfaces. Also,after irradiation, it is believed that the viscosity of the polarsiloxane may increase and improve the binding of the coating tosubstrate.

In some embodiments, the composition is essentially free ofmoisture-curable siloxanes, for example a moisture-curable siloxanecomprising at least two hydroxyl groups, such as for example:

wherein R₂ is alkyl, n ranges from 2 to 4, and x is an integersufficient to give the lubricant a viscosity of about 10 to 2,000,000cst. Other moisture-curable siloxanes which have moisture-curingcharacter as a result of functionality include siloxanes havingfunctional groups such as: alkoxy, aryloxy; oxime; epoxy; —OOCR₁₃,N,N-dialkylamino; N,N-dialkylaminoxy; N-alkylamido; —O—NH—C(O)—R₁₃;—O—C(═NCH₃)—NH—CH₃, —O—C(CH₃)═CH₂; and —S—C₃H₆Si(OCH₃)₃; wherein R₁₃ isH or hydrocarbyl. As used herein, “moisture-curable” means that thesiloxane is curable at ambient conditions in the presence of atmosphericmoisture. As used herein, “essentially free of moisture-curablesiloxanes” means that the composition includes less than about 5 weightpercent of moisture-curable siloxanes, in some embodiments less thanabout 2 weight percent, and in other embodiments is free ofmoisture-curable siloxanes.

The other component of the medical device in contact with the sealingmember can be formed from glass, metal, ceramic, plastic, rubber orcombinations thereof. In some embodiments, the component is preparedfrom one or more olefinic polymers, such as polyethylene, polypropylene,poly(1-butene), poly(2-methyl-1-pentene) and/or cyclic polyolefin. Forexample, the polyolefin can be a homopolymer or a copolymer of analiphatic monoolefin, the aliphatic monoolefin preferably having about 2to 6 carbon atoms, such as polypropylene. In some embodiments, thepolyolefin can be basically linear, but optionally may contain sidechains such as are found, for instance, in conventional, low densitypolyethylene. In some embodiments, the polyolefin is at least 50%isotactic. In other embodiments, the polyolefin is at least about 90%isotactic in structure. In some embodiments, syndiotactic polymers canbe used. A non-limiting example of a suitable cyclic polyolefin includesan ethylene-norbornene copolymer such as TOPAS® ethylene-norbornenecopolymer commercially available from Ticona Engineering Polymers ofFlorence, Ky.

The polyolefin can contain a small amount, generally from about 0.1 to10 percent, of an additional polymer incorporated into the compositionby copolymerization with the appropriate monomer. Such copolymers may beadded to the composition to enhance other characteristics of the finalcomposition, and may be, for example, polyacrylate, polyvinyl,polystyrene and the like.

In some embodiments, the other component may be constructed of apolyolefin composition which includes a radiation stabilizing additiveto impart radiation stability to the container, such as a mobilizingadditive which contributes to the radiation stability of the container,such as for example those disclosed in U.S. Pat. Nos. 4,959,402 and4,994,552, assigned to Becton, Dickinson and Company and both of whichare incorporated herein by reference.

Application of a film of coating to the surface of the sealing membermay be accomplished by any suitable method, as, for example, dipping,brushing, spraying and the like. The composition may be applied neat orit may be applied in a solvent, such as low molecular weight silicone,non-toxic chlorinated or fluorinated hydrocarbons, for example,1,1,2-trichloro-1,2,2-trifluoroethane, freon or conventional hydrocarbonsolvents such as alkanes, toluene, petroleum ether and the like wheretoxicology is not considered important. The solvent is subsequentlyremoved by evaporation. The lubricant film may be of any convenientthickness and, in practice, the thickness will be determined by suchfactors as the viscosity of the lubricant and the temperature ofapplication. For reasons of economy, the film preferably is applied asthinly as practical, since no significant advantage is gained by thickerfilms.

The inventive compositions can be fully cured after application orpartially cured to attach them to the substrate, and then fully cured ata later time. For example, air drying will permit partial cure. Thecompositions are initially fluid and can be applied directly to thesubstrate in any suitable manner, for example by dipping, brushing orspraying. The exact thickness of the coating does not appear to becritical and very thin coatings, e.g., one or two microns exhibiteffective lubricating properties. While not necessary for operability,it is desirable that the thickness of the coating be substantiallyuniform throughout.

Curing of the reactive portion can be accomplished by conventionalmethods well known in the art. For example, curing by use of a catalyst,heat curing via oven or radio frequency (RF) are useful methods as wellas the use of gamma, e-beam or ultraviolet radiation. Any mechanismwhich will initiate the hydrosilylation reaction is a useful curingtechnique.

In some embodiments, the coating is at least partially cured byirradiation with an isotope or electron beam. Radiation sterilization inthe form of ionizing radiation commonly is used in hospitals for medicaldevices such as catheters, surgical items and critical care tools. Gammairradiation is the most popular form of radiation sterilization andtypically is used when materials are sensitive to the high temperatureof autoclaving but are compatible with ionizing radiation. Thebactericidal effect of gamma irradiation exerts its microbicidal effectby oxidizing biological tissue, and thus provides a simple, rapid andefficacious method of sterilization. Gamma rays are used either from acobalt-60 (⁶⁰Co) isotope source or from a machine-generated acceleratedelectron source. Sufficient exposures are achieved when the materials tobe sterilized are moved around an exposed ⁶⁰Co source for a definedperiod of time. The most commonly used validated dose for sterilizingmedical devices is about 10 to about 100 kGy, for example 20-50 kGy.

In the case of oven curing, temperatures should range from about 150° toabout 180° C. and residence time in the oven is generally about 30 toabout 40 seconds, depending on the precise formulation. If RF techniquesare used, the coil should conduct enough heat to obtain a substratesurface temperature of about 180° to about 240° C. At thesetemperatures, only about 2 to about 4 seconds are required for cure. Ifgamma radiation techniques are used, the need for hydrosilylationinitiating catalyst is eliminated, since the radiation will start thecure. This technique has the advantage of sterilizing as well, which isuseful in medical applications.

In some embodiments, the coated articles are subjected to asterilization treatment. Many sterilization techniques are availabletoday to sterilize medical devices to eliminate living organisms such asbacteria, yeasts, mold and viruses. Commonly used sterilizationtechniques used for medical devices include autoclaving, ethylene oxide(EtO) or gamma irradiation, as well as more recently introduced systemsthat involve low-temperature gas plasma and vapor phase sterilants.

One common sterilization technique is steam sterilization orautoclaving, which is a relatively simple process that exposes a device,for example, to saturated steam at temperatures of over 120° C. for aminimum of twenty minutes at a pressure of about 120 kPa. The process isusually carried out in a pressure vessel designed to withstand theelevated temperature and pressure to kill microorganisms by destroyingmetabolic and structural components essential to their replication.Autoclaving is the method of choice for sterilization of heat-resistantsurgical equipment and intravenous fluid as it is an efficient,reliable, rapid, relatively simple process that does not result in toxicresidues.

Thus, in some embodiments, the present invention provides a method forlubricating the interface between an inner surface of a chamber and anexterior surface of a rubber sealing member of a medical device,comprising the steps of: (a) applying a coating as described above ontothe exterior surface of the rubber sealing member; and (b) at leastpartially crosslinking the coating of step (a).

In other embodiments, the present invention provides a method forreducing breakout force or breakloose force between an inner surface ofa chamber and an exterior surface of a rubber sealing member of amedical device, comprising the steps of: (a) applying a coating asdescribed above onto the exterior surface of the rubber sealing member;and (b) at least partially crosslinking the coating of step (a).

In other embodiments, the present invention provides a method forreducing sustaining force between an inner surface of a chamber and anexterior surface of a rubber sealing member of a medical device,comprising the steps of: (a) applying a coating as described above ontothe exterior surface of the rubber sealing member; and (b) at leastpartially crosslinking the coating of step (a).

In other embodiments, the present invention provides a method forreducing breakloose and sustaining forces between an inner surface of achamber and an exterior surface of a rubber sealing member of a medicaldevice, comprising the steps of: (a) applying a coating as describedabove onto the exterior surface of the rubber sealing member; and (b) atleast partially crosslinking the coating of step (a).

Breakout forces, breakloose forces and sustaining forces may beconveniently measured on a universal mechanical tester or on a testingmachine of the type having a constant rate of cross-head movement, as,for example an Instron model 1122, as described in detail below.

The present invention is more particularly described in the followingexamples, which are intended to be illustrative only, as numerousmodifications and variations therein will be apparent to those skilledin the art.

EXAMPLES Example 1

In this example, rubber stoppers for a 10 ml syringe were coated with aconventional polydimethylsiloxane or a coating composition according tothe present invention, optionally with an additional topcoat ofconventional polydimethylsiloxane. The syringe barrels were formed frompolypropylene and coated with a conventional polydimethylsiloxane. Thesyringe components were subjected to irradiation, and evaluated forbreakloose force and infusion pump actuation force (sticktion) relatingto pump performance.

Each syringe barrel was lubricated with a conventionalpolydimethylsiloxane having a viscosity of 12,500 cst. Helvoet FM457butyl rubber syringe stoppers were coated with (a) a conventionalpolydimethylsiloxane having a viscosity of 100,000 cst (“Control”); (b)a cured coating prepared from a coating composition consisting of amixture of 50 weight percent of GE LSR Topcoat Part A and 50 weightpercent of GE LSR Topcoat Part B according to the present invention(“Sample A”); or (c) first with a cured coating prepared from a coatingcomposition consisting of a mixture of 50 weight percent of GE LSRTopcoat Part A and 50 weight percent of GE LSR Topcoat Part B accordingto the present invention and then topcoated with a conventionalpolydimethylsiloxane having a viscosity of 100,000 cst (“Sample B”).

Each stoppper was cured in an oven at a temperature of about 130-140 Cfor about 10 to about 20 minutes. Each syringe was assembled and filledwith 10 ml of saline solution available from VWR Products and autoclavedat 124° C. for 30 minutes.

The breakloose force (in Newtons) of each sample syringe to simulatefast speed injection was determined by an Instron Model No. 1122 incompression (injection) mode using a 50 kg compression load cell at across head speed of 100 mm/min. The breakloose force is visuallydetermined as the highest peak of the curve or point of where the slopeof the curve changes on the graph. The minimum sustaining force isdetermined as the lowest or smooth section of the curve after thebreakloose force. The maximum sustaining force is determined as thehighest section of the curve after the breakloose force. The valuesreported in Table 1 below are the average of five samples for each ofSamples A and B and the Control.

The infusion pump actuation force and fluid delivery characteristics foreach test syringe were evaluated using an Becton Dickinson Program 2eight pump data acquisition system. Each syringe is filled with 10 ml ofDeionized water. All air bubbles in the syringe were removed and theplunger rod was advanced until the sealing rib of the stopper coincidedwith the desired test volume marking on the scale. Microbore tubing(0.020″ ID×60″ length) was connected to the syringe and the other endwas connected to a 23 gauge×1 inch length needle. The needle wasinserted into a beaker. The tubing set was manually filled with waterfrom the syringe and the syringe was mounted in the pump. The flange ofthe barrel contected the front of the flange slot. The syringe plungerrod was positioned against the syringe pusher. There was no gap betweenthe load cell and the plunger rod. The pump was purged by setting theflow rate at the maximum speed allowed by the pump. Once fluid isflowing freely through the tubing and needle into the beaker, thespecified flow rate was set on the pump and infusion was begun. A chartof force over time for each syringe was generated, as shown in FIGS.1-7. A visual determination of sticktion or no sticktion was made byviewing each chart for the smoothness of the curve. A smooth curveindicated no sticktion and an irregularly-shaped curve (for example withdiscernable peaks) indicated sticktion.

TABLE 1 Sample A Sample B Control Breakloose 22.7 ± 0.7 22.4 ± 1.3 33.2± 2.8 Force (N) Sustaining 10.5 ± 0.9  8.2 ± 0.8  6.7 ± 1.2 Force (N)Maximum Pump Actu- ation Force 0.1 ml/hr 0.66; no sticktion N/A   1.77:no sticktion 1.0 ml/hr 0.91: no sticktion N/A 4.82: sticktion  10 ml/hr0.49: no sticktion 0.42: no sticktion 1.30: sticktion

As shown in Table 1 above and with reference to FIGS. 1-7, Sample Acoated with a coating system according to the present invention exhibitslower breakloose force and reduced sticktion, compared to the Controlsample coated with a conventional polydimethylsiloxane. Overcoating witha conventional polydimethylsiloxane, as in Sample B, did not appreciablylower the maximum pump actuation force.

Example 2

In this example, 10 ml syringe components were evaluated in the samemanner as in Example 1 above, except the syringe barrel was formed acyclic polyolefin. Sample C was prepared in the same manner as Sample Aabove. Sample D was prepared in the same manner as Sample B above. Testresults are reported in Table 2 below.

TABLE 2 Sample C Sample D Control Breakloose Force (N) 18.9 ± 1.7 19.2 ±1.9 28.1 ± 10.1 Sustaining Force (N) 10.1 ± 0.7 10.8 ± 0.8 7.8 ± 0.2

As shown in Table 2 above, Sample C coated with a coating systemaccording to the present invention exhibits lower breakloose forcecompared to the Control sample coated with a conventionalpolydimethylsiloxane. Overcoating with a conventionalpolydimethylsiloxane, as in Sample B, did not appreciably affect thebreakloose or sustaining forces.

The present invention has been described with reference to specificdetails of particular embodiments thereof. It is not intended that suchdetails be regarded as limitations upon the scope of the inventionexcept insofar as and to the extent that they are included in theaccompanying claims.

What is claimed is:
 1. A syringe assembly comprising: (a) a chambercomprising an inner surface for containing a medicament; and (b) arubber sealing member formed from silicone rubber and having an exteriorsurface adapted to sealingly engage an inner surface of a chamber of thesyringe assembly, the exterior surface of the sealing member having acoating thereon prepared from a curable composition comprising: (a) afirst organopolysiloxane comprising at least two alkenyl groups; (b) asecond organopolysiloxane comprising at least two pendant hydrogengroups, the second organopolysiloxane being different from the firstorganopolysiloxane; and (c) a cyclic organosiloxane.
 2. The syringeassembly according to claim 1, wherein the rubber sealing member isselected from the group consisting of a stopper, O-ring, plunger tip andpiston.
 3. The syringe assembly according to claim 1, wherein eachalkenyl group of the first organopolysiloxane (a) is independentlyselected from the group consisting of vinyl, allyl, propenyl, butenyl,pentenyl, hexenyl, heptenyl, octenyl, nonenyl and decenyl.
 4. Thesyringe assembly according to claim 1, wherein at least one alkenylgroup of organopolysiloxane (a) is vinyl.
 5. The syringe assemblyaccording to claim 4, wherein the first organopolysiloxane (a) is(7.0-8.0% vinylmethylsiloxane) - dimethylsiloxane copolymer,trimethylsiloxy terminated.
 6. The syringe assembly according to claim1, wherein the first organopolysiloxane (a) comprises at least onefluoro group.
 7. The syringe assembly according to claim 1, wherein thefirst organopolysiloxane (a) comprises about 5 to about 50 weightpercent of the composition.
 8. The syringe assembly according to claim1, wherein the second organopolysiloxane (b) is represented by thestructural formulae (V):

wherein p is about 8 to about
 12. 9. The syringe assembly according toclaim 1, wherein the second organopolysiloxane (b) is represented by thestructural formulae (VI):HMe₂SiO(Me₂SiO)_(p)SiMe₂H  (VI) wherein p is about 140 to about
 170. 10.The syringe assembly according to claim 1, wherein the secondorganopolysiloxane (b) is selected from the group consisting ofdimethylhydro terminated polydimethylsiloxanes; methylhydro,dimethylpolysiloxanecopolymers; methylhydro methyloctyl siloxanecopolymers; and methylhydro, phenylmethyl siloxane copolymers.
 11. Thesyringe assembly according to claim 1, wherein the secondorganopolysiloxane (b) comprises at least one fluoro group.
 12. Thesyringe assembly according to claim 1, wherein the secondorganopolysiloxane (b) comprises about 1 to about 40 weight percent ofthe composition.
 13. The syringe assembly according to claim 1, whereinthe curable composition further comprises at least one additionalcomponent selected from the group consisting of fluorocarbon oligomers,fluorocarbon polymers and fluoro organopolysiloxanes.
 14. The syringeassembly according to claim 1, wherein the curable composition furthercomprises at least one additional component comprising at least onefluoro group selected from the group consisting of fluorine groups andfluoroalkyl groups.
 15. The syringe assembly according to claim 1,wherein the at least one cyclic siloxane is selected from the groupconsisting of octamethylcyclotetrasiloxane anddecamethylcyclopentasiloxane.
 16. The syringe assembly according toclaim 1, wherein the cyclic siloxane comprises about 5 to about 80weight percent of the composition.
 17. The syringe assembly according toclaim 1, wherein the composition further comprises polydimethylsiloxane.18. The syringe assembly according to claim 17, wherein thepolydimethylsiloxane comprises about 1 to about 20 weight percent of thecomposition.
 19. The syringe assembly according to claim 1, wherein thecomposition further comprises silica.
 20. The syringe assembly accordingto claim 19, wherein the silica comprises about 1 to about 15 weightpercent of the composition.
 21. The syringe assembly according to claim1, wherein the composition further comprises a catalytic amount of acatalyst for promoting crosslinking of the first organopolysiloxane (a)and the second organopolysiloxane (b).
 22. The syringe assemblyaccording to claim 1, wherein the chamber is formed from glass, metal,ceramic, plastic, rubber or combinations thereof.
 23. The syringeassembly according to claim 22, wherein the chamber is prepared from anolefinic polymer.
 24. The syringe assembly according to claim 23,wherein the olefinic polymer is selected from the group consisting ofpolyethylene, polypropylene, poly(1-butene), poly(2-methyl-1-pentene)and cyclic polyolefins.
 25. The syringe assembly according to claim 24,wherein the chamber is prepared from a cyclic polyolefin.
 26. A methodfor lubricating the interface between an inner surface of a chamber andan exterior surface of a silicone rubber sealing member of a syringeassembly, comprising the steps of: (a) applying a coating onto theexterior surface of the silicone rubber sealing member, the coatingbeing prepared from a curable composition comprising: (i) a firstorganopolysiloxane comprising at least two alkenyl groups; (ii) a secondorganopolysiloxane comprising at least two pendant hydrogen groups, thesecond organopolysiloxane being different from the firstorganopolysiloxane; and (iii) a cyclic organosiloxane; and (b) at leastpartially crosslinking the coating of step (a).
 27. A method forreducing breakout force or breakloose force between an inner surface ofa chamber and an exterior surface of a silicone rubber sealing member ofa syringe assembly, comprising the steps of: (a) applying a coating ontothe exterior surface of the silicone rubber sealing member, the coatingbeing prepared from a curable composition comprising: (i) a firstorganopolysiloxane comprising at least two alkenyl groups; (ii) a secondorganopolysiloxane comprising at least two pendant hydrogen groups, thesecond organopolysiloxane being different from the firstorganopolysiloxane; and (iii) a cyclic organosiloxane; and (b) at leastpartially crosslinking the coating of step (a).
 28. A method forreducing sustaining force between an inner surface of a chamber and anexterior surface of a silicone rubber sealing member of a syringeassembly, comprising the steps of: (a) applying a coating onto theexterior surface of the silicone rubber sealing member, the coatingbeing prepared from a curable composition comprising: (i) a firstorganopolysiloxane comprising at least two alkenyl groups; (ii) a secondorganopolysiloxane comprising at least two pendant hydrogen groups, thesecond organopolysiloxane being different from the firstorganopolysiloxane; and (iii) a cyclic organosiloxane; and (b) at leastpartially crosslinking the coating of step (a).
 29. A method forreducing breakloose and sustaining forces between an inner surface of achamber and an exterior surface of a silicone rubber sealing member of asyringe assembly, comprising the steps of: (a) applying a coating ontothe exterior surface of the silicone rubber sealing member, the coatingbeing prepared from a curable composition comprising: (i) a firstorganopolysiloxane comprising at least two alkenyl groups; (ii) a secondorganopolysiloxane comprising at least two pendant hydrogen groups, thesecond organopolysiloxane being different from the firstorganopolysiloxane; and (iii) a cyclic organosiloxane; and (b) at leastpartially crosslinking the coating of step (a).
 30. A syringe assemblycomprising: (a) a chamber comprising an inner surface for containing amedicament; and (b) a rubber sealing member formed from silicone rubberand having an exterior surface adapted to sealingly engage an innersurface of a chamber of the syringe assembly, the exterior surface ofthe sealing member having a coating thereon prepared from a curablecomposition comprising: (a) a first organopolysiloxane comprising atleast two alkenyl groups; and (b) a second organopolysiloxane comprisingat least two pendant hydrogen groups, the second organopolysiloxanebeing different from the first organopolysiloxane, wherein at least oneof the first organopolysiloxane and the second organopolysiloxane of thecurable composition comprises at least one fluoro group.
 31. The syringeassembly according to claim 30, wherein the rubber sealing member isselected from the group consisting of a stopper, 0-ring, plunger tip andpiston.
 32. The syringe assembly according to claim 30, wherein eachalkenyl group of the first organopolysiloxane (a) is independentlyselected from the group consisting of vinyl, allyl, propenyl, butenyl,pentenyl, hexenyl, heptenyl, octenyl, nonenyl and decenyl.
 33. Thesyringe assembly according to claim 30, wherein at least one alkenylgroup of organopolysiloxane (a) is vinyl.
 34. The syringe assemblyaccording to claim 33, wherein the first organopolysiloxane (a) is(7.0-8.0% vinylmethylsiloxane) - dimethylsiloxane copolymer,trimethylsiloxy terminated.
 35. The syringe assembly according to claim30, wherein the first organopolysiloxane (a) comprises at least onefluoro group.
 36. The syringe assembly according to claim 30, whereinthe first organopolysiloxane (a) comprises about 5 to about 50 weightpercent of the composition.
 37. The syringe assembly according to claim30, wherein the second organopolysiloxane (b) is represented by thestructural formulae (V):

wherein p is about 8 to about
 12. 38. The syringe assembly according toclaim 30, wherein the second organopolysiloxane (b) is represented bythe structural formulae (VI):HMe₂SiO(Me₂SiO)_(p)SiMe₂H  (VI) wherein p is about 140 to about
 170. 39.The syringe assembly according to claim 30, wherein the secondorganopolysiloxane (b) is selected from the group consisting ofdimethylhydro terminated polydimethylsiloxanes; methylhydro,dimethylpolysiloxanecopolymers; methylhydro methylctyl siloxanecopolymers; and methylhydro, phenylmethyl siloxane copolymers.
 40. Thesyringe assembly according to claim 30, wherein the secondorganopolysiloxane (b) comprises at least one fluoro group.
 41. Thesyringe assembly according to claim 30, wherein the secondorganopolysiloxane (b) comprises about 1 to about 40 weight percent ofthe composition.
 42. The syringe assembly according to claim 30, whereinthe composition further comprises at least one additional componentselected from the group consisting of fluorocarbon oligomers,fluorocarbon polymers and fluoro organopolysiloxanes.
 43. The syringeassembly according to claim 30, wherein the composition furthercomprises at least one additional component comprising at least onefluoro group selected from the group consisting of fluorine groups andfluoroalkyl groups.
 44. The syringe assembly according to claim 30,wherein the composition further comprises polydimethylsiloxane.
 45. Thesyringe assembly according to claim 44, wherein the polydimethylsiloxanecomprises about 1 to about 20 weight percent of the composition.
 46. Thesyringe assembly according to claim 30, wherein the composition furthercomprises silica.
 47. The syringe assembly according to claim 46,wherein the silica comprises about 1 to about 15 weight percent of thecomposition.
 48. The syringe assembly according to claim 30, wherein thecomposition further comprises a catalytic amount of a catalyst forpromoting crosslinking of the first organopolysiloxane (a) and thesecond organopolysiloxane (b).
 49. The syringe assembly according toclaim 30, wherein the chamber is formed from glass, metal, ceramic,plastic, rubber or combinations thereof.
 50. The syringe assemblyaccording to claim 49, wherein the chamber is prepared from an olefinicpolymer.
 51. The syringe assembly according to claim 50, wherein theolefinic polymer is selected from the group consisting of polyethylene,polypropylene, poly(1-butene), poly(2-methyl-1-pentene) and cyclicpolyolefins.
 52. The syringe assembly according to claim 51, wherein thechamber is prepared from a cyclic polyolefin.
 53. A method forlubricating the interface between an inner surface of a chamber and anexterior surface of a silicone rubber sealing member of a syringeassembly, comprising the steps of: (a) applying a coating onto theexterior surface of the rubber sealing member, the coating beingprepared from a curable composition comprising: (i) a firstorganopolysiloxane comprising at least two alkenyl groups; and (ii) asecond organopolysiloxane comprising at least two pendant hydrogengroups, the second organopolysiloxane being different from the firstorganopolysiloxane, wherein at least one of the first organopolysiloxaneand the second organopolysiloxane comprises at least one fluoro group;and (b) at least partially crosslinking the coating of step (a).
 54. Amethod for reducing breakout force or breakloose force between an innersurface of a chamber and an exterior surface of a silicone rubbersealing member of a syringe assembly, comprising the steps of: (a)applying a coating onto the exterior surface of the rubber sealingmember, the coating being prepared from a curable compositioncomprising: (i) a first organopolysiloxane comprising at least twoalkenyl groups; and (ii) a second organopolysiloxane comprising at leasttwo pendant hydrogen groups, the second organopolysiloxane beingdifferent from the first organopolysiloxane, wherein at least one of thefirst organopolysiloxane and the second organopolysiloxane comprises atleast one fluoro group; and (b) at least partially crosslinking thecoating of step (a).
 55. A method for reducing sustaining force betweenan inner surface of a chamber and an exterior surface of a siliconerubber sealing member of a syringe assembly, comprising the steps of:(a) applying a coating onto the exterior surface of the rubber sealingmember, the coating being prepared from a curable compositioncomprising: (i) a first organopolysiloxane comprising at least twoalkenyl groups; and (ii) a second organopolysiloxane comprising at leasttwo pendant hydrogen groups, the second organopolysiloxane beingdifferent from the first organopolysiloxane, wherein at least one of thefirst organopolysiloxane and the second organopolysiloxane comprises atleast one fluoro group; and (b) at least partially crosslinking thecoating of step (a).
 56. A method for reducing breakloose and sustainingforces between an inner surface of a chamber and an exterior surface ofa rubber sealing member of a syringe assembly, comprising the steps of:(a) applying a coating onto the exterior surface of the rubber sealingmember, the coating being prepared from a curable compositioncomprising: (i) a first organopolysiloxane comprising at least twoalkenyl groups; and (ii) a second organopolysiloxane comprising at leasttwo pendant hydrogen groups, the second organopolysiloxane beingdifferent from the first organopolysiloxane, wherein at least one of thefirst organopolysiloxane and the second organopolysiloxane comprises atleast one fluoro group; and (b) at least partially crosslinking thecoating of step (a).